ABSTRACT
The ability to restrict low molecular weight compounds to the gastrointestinal (GI) tract may enable an enhanced therapeutic index for molecular targets known to be associated with systemic toxicity. Using a triazolopyrazine CSF1R inhibitor scaffold, a broad range of prodrugs were synthesized and evaluated for enhanced delivery to the colon in mice. Subsequently, the preferred cyclodextrin prodrug moiety was appended to a number of CSF1R inhibitory active parent molecules, enabling GI-restricted delivery. Evaluation of a cyclodextrin prodrug in a dextran sodium sulfate (DSS)-induced mouse colitis model resulted in enhanced GI tissue levels of active parent. At a dose where no significant depletion of systemic monocytes were detected, the degree of pharmacodynamic effect-measured as reduction in macrophages in the colon-was inferior to that observed with a systemically available positive control. This suggests that a suitable therapeutic index cannot be achieved with CSF1R inhibition by using GI-restricted delivery in mice. However, these efforts provide a comprehensive frame-work in which to pursue additional gut-restricted delivery strategies for future GI targets.
Subject(s)
Colitis/immunology , Cyclodextrins/chemistry , Prodrugs/administration & dosage , Prodrugs/chemical synthesis , Receptors, Granulocyte-Macrophage Colony-Stimulating Factor/antagonists & inhibitors , Animals , Colitis/chemically induced , Colitis/drug therapy , Colon/chemistry , Dextran Sulfate/adverse effects , Disease Models, Animal , Drug Evaluation, Preclinical , Female , Macrophages/drug effects , Macrophages/metabolism , Mice , Models, Molecular , Molecular Structure , Prodrugs/chemistry , Prodrugs/pharmacokineticsABSTRACT
Previous work investigating tricyclic pyrrolopyrazines as kinase cores led to the discovery that 1-cyclohexyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazine (12) had Jak inhibitory activity. Herein we describe our initial efforts to develop orally bioavailable analogs of 12 with improved selectivity of Jak1 over Jak2.
Subject(s)
Janus Kinase 1/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrazines/pharmacology , Triazoles/pharmacology , Animals , Cell Line , Dose-Response Relationship, Drug , Humans , Janus Kinase 1/metabolism , Male , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Pyrazines/chemical synthesis , Pyrazines/chemistry , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Triazoles/chemical synthesis , Triazoles/chemistryABSTRACT
We previously demonstrated that selective inhibition of protein kinase Cθ (PKCθ) with triazinone 1 resulted in dose-dependent reduction of paw swelling in a mouse model of arthritis.1,2 However, a high concentration was required for efficacy, thus providing only a minimal safety window. Herein we describe a strategy to deliver safer compounds based on the hypothesis that optimization of potency in concert with good oral pharmacokinetic (PK) properties would enable in vivo efficacy at reduced exposures, resulting in an improved safety window. Ultimately, transformation of 1 yielded analogues that demonstrated excellent potency and PK properties and fully inhibited IL-2 production in an acute model. In spite of good exposure, twice-a-day treatment with 17l in the glucose-6-phosphate isomerase chronic in vivo mouse model of arthritis yielded only moderate efficacy. On the basis of the exposure achieved, we conclude that PKCθ inhibition alone is insufficient for complete efficacy in this rodent arthritis model.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Arthritis, Experimental/drug therapy , Isoenzymes/antagonists & inhibitors , Protein Kinase C/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/metabolism , Arthritis, Experimental/metabolism , Crystallography, X-Ray , Disease Models, Animal , Humans , Interleukin-2/metabolism , Isoenzymes/chemistry , Isoenzymes/metabolism , Male , Mice , Models, Chemical , Models, Molecular , Molecular Structure , Protein Binding , Protein Kinase C/chemistry , Protein Kinase C/metabolism , Protein Kinase C-theta , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Protein Structure, Tertiary , Treatment OutcomeABSTRACT
Protein kinase Cθ (PKCθ) regulates a key step in the activation of T cells. On the basis of its mechanism of action, inhibition of this kinase is hypothesized to serve as an effective therapy for autoimmune diseases such as rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and psoriasis. Herein, the discovery of a small molecule PKCθ inhibitor is described, starting from a fragment hit 1 and advancing to compound 41 through the use of structure-based drug design. Compound 41 demonstrates excellent in vitro activity, good oral pharmacokinetics, and efficacy in both an acute in vivo mechanistic model and a chronic in vivo disease model but suffers from tolerability issues upon chronic dosing.
Subject(s)
Isoenzymes/antagonists & inhibitors , Isoenzymes/chemistry , Protein Kinase C/antagonists & inhibitors , Protein Kinase C/chemistry , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Administration, Oral , Animals , Area Under Curve , Arthritis, Experimental/drug therapy , Biological Availability , Cells, Cultured , Chromatography, Liquid , Crystallography, X-Ray , Dose-Response Relationship, Drug , Drug Design , Drug Discovery , Female , Humans , Isoenzymes/metabolism , Mass Spectrometry , Mice, Inbred BALB C , Mice, Inbred DBA , Models, Molecular , Molecular Structure , Protein Binding , Protein Kinase C/metabolism , Protein Kinase C-theta , Protein Kinase Inhibitors/pharmacokinetics , Protein Structure, Tertiary , Rats , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacokinetics , Small Molecule Libraries/pharmacology , T-Lymphocytes/drug effectsABSTRACT
We report the SAR around a series of 2,4-diaminopyrimidine-5-carboxamide inhibitors of Sky kinase. 2-Aminophenethyl analogs demonstrate excellent potency but moderate kinase selectivity, while 2-aminobenzyl analogs that fill the Ala571 subpocket exhibit good inhibition activity and excellent kinase selectivity.
Subject(s)
Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Amides/chemistry , Amides/pharmacology , Animals , Humans , Mice , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Optimization of the ADME properties of a series of 2,4-diaminopyrimidine-5-carboxamide inhibitors of Sky kinase resulted in the identification of highly selective compounds with properties suitable for use as in vitro and in vivo tools to probe the effects of Sky inhibition.
Subject(s)
Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Amides/chemistry , Amides/pharmacology , Animals , Humans , Mice , Receptor Protein-Tyrosine Kinases/chemistry , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Mining of an in-house collection of angiotensin II type 1 receptor antagonists to identify compounds with activity at the peroxisome proliferator-activated receptor-γ (PPARγ) revealed a new series of imidazo[4,5-b]pyridines 2 possessing activity at these two receptors. Early availability of the crystal structure of the lead compound 2a bound to the ligand binding domain of human PPARγ confirmed the mode of interaction of this scaffold to the nuclear receptor and assisted in the optimization of PPARγ activity. Among the new compounds, (S)-3-(5-(2-(1H-tetrazol-5-yl)phenyl)-2,3-dihydro-1H-inden-1-yl)-2-ethyl-5-isobutyl-7-methyl-3H-imidazo[4,5-b]pyridine (2l) was identified as a potent angiotensin II type I receptor blocker (IC(50) = 1.6 nM) with partial PPARγ agonism (EC(50) = 212 nM, 31% max) and oral bioavailability in rat. The dual pharmacology of 2l was demonstrated in animal models of hypertension (SHR) and insulin resistance (ZDF rat). In the SHR, 2l was highly efficacious in lowering blood pressure, while robust lowering of glucose and triglycerides was observed in the male ZDF rat.
Subject(s)
Angiotensin II Type 1 Receptor Blockers/chemical synthesis , Antihypertensive Agents/chemical synthesis , Hypoglycemic Agents/chemical synthesis , Imidazoles/chemical synthesis , PPAR gamma/agonists , Pyridines/chemical synthesis , Administration, Oral , Angiotensin II Type 1 Receptor Blockers/chemistry , Angiotensin II Type 1 Receptor Blockers/pharmacology , Animals , Antihypertensive Agents/chemistry , Antihypertensive Agents/pharmacology , Biological Availability , Blood Glucose/analysis , Crystallography, X-Ray , Drug Partial Agonism , Humans , Hypoglycemic Agents/chemistry , Hypoglycemic Agents/pharmacology , Imidazoles/chemistry , Imidazoles/pharmacology , Insulin Resistance , Male , Models, Molecular , Pyridines/chemistry , Pyridines/pharmacology , Radioligand Assay , Rats , Rats, Inbred SHR , Stereoisomerism , Structure-Activity Relationship , Transcriptional Activation , Triglycerides/bloodSubject(s)
Chemistry, Pharmaceutical , Informatics , Algorithms , Drug Design , Humans , Structure-Activity RelationshipABSTRACT
Aiming to improve upon previously disclosed Factor Xa inhibitors, a series of 4,4-disubstituted pyrrolidine-1,2-dicarboxamides were explored with the intent of increasing the projected human half-life versus 5 (projected human t(1/2)=6 h). A stereospecific route to compounds containing a 4-aryl-4-hydroxypyrrolidine scaffold was developed, resulting in several compounds that demonstrated an increase in the half-life as well as an increase in the in vitro potency compared to 5. Reported herein is the discovery of 26, containing a (2R,4S)-4-hydroxy-4-(2,4-difluorophenyl)-pyrrolidine scaffold, which is a selective, orally bioavailable, efficacious Factor Xa inhibitor that appears suitable for a once-daily dosing (projected human t(1/2)=23 h).
Subject(s)
Pyrrolidines/pharmacology , Administration, Oral , Crystallography, X-Ray , Half-Life , Humans , Pyrrolidines/administration & dosage , Pyrrolidines/pharmacokineticsABSTRACT
Herein, we report the discovery of novel, proline-based factor Xa inhibitors containing a neutral P1 chlorophenyl pharmacophore. Through the additional incorporation of 1-(4-amino-3-fluoro-phenyl)-1H-pyridin-2-one 22, as a P4 pharmacophore, we discovered compound 7 (PD 0348292). This compound is a selective, orally bioavailable, efficacious FXa inhibitor that is currently in phase II clinical trials for the treatment and prevention of thrombotic disorders.
Subject(s)
Antithrombin III/chemical synthesis , Antithrombin III/pharmacology , Pyridones/chemical synthesis , Pyridones/pharmacology , Pyrrolidines/chemical synthesis , Pyrrolidines/pharmacology , Animals , Anticoagulants/chemical synthesis , Anticoagulants/pharmacokinetics , Anticoagulants/pharmacology , Antithrombin III/pharmacokinetics , Crystallography, X-Ray , Dogs , Humans , Male , Pyridones/pharmacokinetics , Pyrrolidines/pharmacokinetics , Rabbits , Rats , Structure-Activity RelationshipABSTRACT
We report the design and synthesis of a series of 6-(2,4-diaminopyrimidinyl)-1,4-benzoxazin-3-ones as orally bioavailable small molecule inhibitors of renin. Compounds with a 2-methyl-2-aryl substitution pattern exhibit potent renin inhibition and good permeability, solubility, and metabolic stability. Oral bioavailability was found to be dependent on metabolic clearance and cellular permeability, and was optimized through modulation of the sidechain that binds in the S3(sp) subsite.
Subject(s)
Benzoxazines/chemistry , Benzoxazines/pharmacology , Drug Design , Pyridines/chemistry , Renin/antagonists & inhibitors , Amination , Animals , Benzoxazines/chemical synthesis , Benzoxazines/metabolism , Crystallography, X-Ray , Male , Models, Molecular , Molecular Structure , Rats , Rats, Sprague-Dawley , Renin/chemistry , Renin/metabolism , Structure-Activity RelationshipABSTRACT
A novel series of pyrrolidine-1,2-dicarboxamides was discovered as factor Xa inhibitors using structure-based drug design. This series consisted of a neutral 4-chlorophenylurea P1, a biphenylsulfonamide P4 and a D-proline scaffold (1, IC(50) = 18 nM). Optimization of the initial hit resulted in an orally bioavailable, subnanomolar inhibitor of factor Xa (13, IC(50) = 0.38 nM), which was shown to be efficacious in a canine electrolytic model of thrombosis with minimal bleeding.
Subject(s)
Antithrombin III/chemistry , Chemistry, Pharmaceutical/methods , Pyrrolidonecarboxylic Acid/pharmacology , Administration, Oral , Animals , Antithrombin III/pharmacology , Crystallization , Dogs , Drug Design , Humans , Inhibitory Concentration 50 , Models, Chemical , Models, Molecular , Protein Binding , Pyrrolidonecarboxylic Acid/chemistry , Structure-Activity Relationship , Time FactorsABSTRACT
Novel 2,4-diaminopyrimidine-based small molecule renin inhibitors are disclosed. Through high throughput screening, parallel synthesis, X-ray crystallography, and structure based drug design, we have developed the first non-chiral, non-peptidic, small molecular template to possess moderate potency against renin. The designed compounds consist of a novel 6-ethyl-5-(1,2,3,4-tetrahydroquinolin-7-yl)pyrimidine-2,4-diamine ring system that exhibit moderate potency (IC(50): 91-650 nM) against renin while remaining 'Rule-of-five' compliant.
Subject(s)
Chemistry, Pharmaceutical/methods , Pyrimidines/chemistry , Renin/antagonists & inhibitors , Animals , Crystallography, X-Ray , Drug Design , Inhibitory Concentration 50 , Models, Chemical , Models, Molecular , Molecular Conformation , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , Rats , Rats, Sprague-Dawley , Structure-Activity RelationshipABSTRACT
Herein, we report on the identification of three potent glycine and related amino acid-based series of FXa inhibitors containing a neutral P1 chlorophenyl pharmacophore. A X-ray crystal structure has shown that constrained glycine derivatives with optimized N-substitution can greatly increase hydrophobic interactions in the FXa active site. Also, the substitution of a pyridone ring for a phenylsulfone ring in the P4 sidechain resulted in an inhibitor with enhanced oral bioavailability.
Subject(s)
Factor Xa Inhibitors , Factor Xa/chemistry , Glycine/analogs & derivatives , Glycine/chemistry , Serine Proteinase Inhibitors/chemistry , Crystallography, X-Ray , Humans , Molecular Structure , Protein ConformationABSTRACT
A systematic investigation of the S3 sub-pocket activity requirements was conducted. It was observed that linear and sterically small side chain substituents are preferred in the S3 sub-pocket for optimal renin inhibition. Polar groups in the S3-sub-pocket were not well tolerated and caused a reduction in renin inhibitory activity. Further, compounds with clog P's < or = 3 demonstrated a dramatic reduction in CYP3A4 inhibitory activity.
Subject(s)
Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Piperazines/chemistry , Piperazines/pharmacology , Renin/antagonists & inhibitors , Crystallography, X-Ray , Cytochrome P-450 CYP3A , Cytochrome P-450 Enzyme System/drug effects , Enzyme Inhibitors/chemical synthesis , Humans , Models, Molecular , Molecular Structure , Piperazines/chemical synthesis , Stereoisomerism , Structure-Activity RelationshipABSTRACT
The activated factor VII/tissue factor complex (FVIIa/TF) is known to play a key role in the formation of blood clots. Inhibition of this complex may lead to new antithrombotic drugs. A fluoropyridine-based series of FVIIa/TF inhibitors was discovered which utilized a diisopropylamino group for binding in the S2 and S3 binding pockets of the active site of the enzyme complex. In this series, an enhancement in binding affinity was observed by substitution at the 5-position of the hydroxybenzoic acid sidechain. An X-ray crystal structure indicates that amides at this position may increase inhibitor binding affinity through interactions with the S1'/S2' pocket.
Subject(s)
Enzyme Inhibitors/pharmacology , Factor VIIa/antagonists & inhibitors , Pyridines/pharmacology , Thromboplastin/antagonists & inhibitors , Crystallography, X-Ray , Drug Evaluation, Preclinical , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Models, Molecular , Molecular Structure , Pyridines/chemical synthesis , Pyridines/chemistry , Structure-Activity RelationshipABSTRACT
Inhibition of renin enzymatic activity by a series of ketopiperazine-based compounds containing a C6 benzyloxymethyl substituent correlated with a +(pi+sigma) effect. A 3-pyridinyloxymethyl substituent was also found to be equipotent as higher molecular weight analogs, and exhibited decreased CYP3A4 inhibition levels and improved pharmacokinetic properties.
Subject(s)
Piperazines/chemical synthesis , Renin/antagonists & inhibitors , Antihypertensive Agents/chemical synthesis , Antihypertensive Agents/pharmacokinetics , Caco-2 Cells , Cell Membrane Permeability , Cytochrome P-450 CYP3A , Cytochrome P-450 Enzyme Inhibitors , Ether , Humans , Inhibitory Concentration 50 , Piperazine , Piperazines/pharmacokinetics , Piperazines/pharmacology , Solubility , Structure-Activity RelationshipABSTRACT
The activated Factor VII/tissue factor complex (FVIIa/TF) plays a key role in the formation of blood clots. Inhibition of this complex may lead to new antithrombotic drugs. An X-ray crystal structure of a fluoropyridine-based FVIIa/TF inhibitor bound in the active site of the enzyme complex suggested that incorporation of substitution at the 5-position of the hydroxybenzoic acid side chain could lead to the formation of more potent inhibitors through interactions with the S1'/S2' pocket.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Factor VIIa/chemistry , Fibrinolytic Agents/chemical synthesis , Pyridines/chemical synthesis , Thromboplastin/chemistry , Binding Sites , Crystallography, X-Ray , Enzyme Inhibitors/chemistry , Factor VIIa/antagonists & inhibitors , Factor Xa Inhibitors , Fibrinolytic Agents/chemistry , Fibrinolytic Agents/pharmacology , Humans , Inhibitory Concentration 50 , Protein Binding , Prothrombin Time , Pyridines/chemistry , Structure-Activity Relationship , Thromboplastin/antagonists & inhibitorsABSTRACT
We have found that both enantiomeric configurations of the 6-alkoxymethyl-1-aryl-2-piperazinone scaffold display equipotent renin inhibition activity and similar SAR patterns. This enantiomeric flexibility is in contrast to a previously reported 3-alkoxymethyl-4-arylpiperidine scaffold.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Piperazines/chemical synthesis , Piperazines/pharmacology , Renin/antagonists & inhibitors , Binding Sites , Enzyme Inhibitors/chemistry , Indicators and Reagents , Molecular Conformation , Molecular Structure , Piperazines/chemistry , Protein Conformation , Renin/chemistry , StereoisomerismABSTRACT
Ketopiperazine 2 was designed from a previously published analog. Compound 2 was shown to be a novel, potent inhibitor of renin that, when administered orally, lowered blood pressure in a hypertensive double transgenic (human renin and angiotensinogen) mouse model. Compound 2 was further optimized to sub-nanomolar potency by designing an analog that addressed the S3 sub-pocket of the renin enzyme (16).